The Western European Union (WEU; French: Union de l'Europe occidentale, UEO) was an international organisation and military alliance, tasked with implementing the Modified Treaty of Brussels (1954), an amended version of the original 1948 Treaty of Brussels. The WEU was established by seven European nations allied with the USA (Capitalist Bloc and NATO members) during the Cold War.

Since the end of the Cold War, WEU tasks and institutions have been gradually transferred to the Common Security and Defence Policy of the geographically larger, and in terms of integration more comprehensive, European Union. This process was completed in 2009, when a solidarity clause between the member states of the European Union which was similar (but not identical) to the WEU's mutual defence clause, entered into force with the Treaty of Lisbon. The states party to the Modified Treaty of Brussels consequently decided to terminate that treaty on 31 March 2010, with all the remaining WEU's activities to be ceased within 15 months. On 30 June 2011 the WEU was officially declared defunct.[1]

The WEU was headquartered in Brussels, with a staff of 65 and an annual budget of €13.4 million.[2] It was composed of the Council of the WEU (the Council) and the Assembly of the WEU (the Assembly).

The WEU was led by a Council of Ministers, assisted by a Permanent Representatives Council on the ambassadorial level. Social and cultural aspects of the Brussels Treaty were handed to the Council of Europe to avoid duplication of responsibilities within Europe.[3] SD help A Parliamentary Assembly (composed of the delegations of the member states to the Parliamentary Assembly of the Council of Europe) supervised the work of the Council, but it did not have any obligations on the Council. The Assembly of WEU was a consultative institution.

The Independent European Program Group (IEPG) was established as a forum for armaments cooperation in 1976 with the aim of creating a European Armaments Agency. Since 1993 the WEU armaments cooperation forum has been known as Western European Armaments Group (WEAG). Its membership reached 19 in 2000: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Italy, Luxembourg, Netherlands, Norway, Poland, Portugal, Spain, Sweden, Turkey and the United Kingdom. The body closed on 23 May 2005.[4]

The Western European Armaments Organisation (WEAO) was intended as an Armaments Agency but operations were limited to a research cell. It provided support services in defence research and technology. It was created in 1996, and closed in August 2006.[5] These agencies were taken over by the European Defence Agency. Other transferred bodies include the Institute for Security Studies and the Satellite Centre.

On 15 May 1995, the Council of Ministers of the WEU met in Lisbon. During this meeting a declaration of the creation of the European Operational Rapid Force (Eurofor) was made by France, Italy, Spain and Portugal. Eurofor became operational in June 1998 as a task force of the Western European Union.[6]

The Western European Union had 10 member countries, 6 associate member countries, 5 observer countries and 7 associate partner countries. On 14 June 2001, then-WEU President Solana stated that there was no foreseeable reason to change the status of the non member countries in the organisation.

Member countries: (modified Brussels Treaty - 1954)

All member countries of the WEU were also members of both NATO and the European Union. These are the only nations that had full voting rights.

1 Denmark was an exception, being member of both. It has an opt-out from the Treaty of Maastricht (1992), so that it does not participate in the CSDP of the European Union. Thus in respect to the WEU it would have been more appropriate for it to be regarded as non-EU NATO member state (WEU associate status).

Associate member countries: (Rome - 1992)

Associate membership was created to include the European countries that were members of NATO but not of the European Union. Associate members Poland, the Czech Republic & Hungary joined the EU in 2004.

The Treaty of Brussels was signed by the United Kingdom, France, Belgium, Luxembourg, and the Netherlands on 17 March 1948. It was a mutual intergovernmental self-defence treaty which also promoted economic, cultural and social collaboration.

As a result of the failure of the European Defence Community on 23 October 1954 the WEU was established by the Paris Agreements with the incorporation of Italy and West Germany. On this occasion it was renamed the Western European Union. The signatories of the Paris Agreements clearly stated their three main objectives in the preamble to the modified Brussels Treaty:

To create in Western Europe a firm basis for European economic recovery;

To afford assistance to each other in resisting any policy of aggression;

To promote the unity and encourage the progressive integration of Europe.

The defence efforts resulting from the Brussels Treaty took form as the Western Union Defence Organisation (see below).

The Brussels Pact had cultural and social clauses, concepts for the setting up of a 'Consultative Council'. The basis for this was that a cooperation between Western nations would help stop the spread of Communism.

A summary of some of the moves towards a merger of the WEU into the EU:

On 20 November 1999, Javier Solana, who is the High Representative for the Common Foreign and Security Policy (CFSP) of the EU, was also appointed Secretary-General of the WEU. His being head of both organisations permits him to oversee the ongoing transfer of functions from the WEU to the EU.

With the transfer of responsibilities, the WEU's Parliamentary assembly was urged to dissolve itself, as it had a mandate to supervise WEU politics, not the EU's CSDP politics. But the Assembly saw itself as playing an important role, particularly with greater right of scrutiny, membership, experience and expertise in defence policy. Therefore, it renamed itself the "Interim European Security and Defence Assembly" and urged the European Convention to include it as a second chamber within the EU's institutional framework. Hence it argued it could effectively scrutinise the CSDP, help improve EU-NATO relations and be more suited, being composed of national parliamentarians, to the intergovernmental style of the CSDP.

However with the European Constitution aiming to streamline and simplify the EU's foreign policy, for example combining the two main foreign policy posts, it was not seen as wise to then create a separate double legislature for the CFSP, instead, the European Parliament was granted greater scrutiny over foreign policy.[12]

In 2009, the Treaty of Lisbon took over the WEU's mutual defence clause.[1] There was much discussion about what to do with the WEU following the introduction of Lisbon, including plans to scrap it.[2] On 30 March 2010 in a Written Ministerial Statement UK's Foreign Office Minister Chris Bryant gave notice that the UK intended to withdraw from the Western European Union within a year.[13] On 31 March 2010 the German Foreign Affairs Ministry announced Germany's intention to withdraw from the Modified Brussels Treaty.[14] That same year, the Spanish Presidency of the WEU, on behalf of the 10 Member States of the Modified Brussels Treaty, announced the collective decision to withdraw from the Treaty and to close the WEU organisation by June 2011.[15] On 30 June 2011 the WEU officially ceased to exist.